Increased Efficiency of GroE-assisted Protein Folding
نویسندگان
چکیده
This study addresses the role of ATP-bound and free Mg and Mn ions in the activation and modulation of chaperonin-assisted refolding of urea-denatured malate dehydrogenase. As compared with Mg, Mn ions caused a significant increase in the rate of GroE-assisted malate dehydrogenase refolding and, concomitantly, a decrease in the rate of ATP hydrolysis. Moreover, Mn increases the affinity of GroES for GroEL, even in the presence of saturating amounts of Mg. Chemical cross-linking showed that lower concentrations of Mn-ATP as compared with Mg-ATP are needed to form both asymmetric GroEL14GroES7 and symmetric GroEL14(GroES7)2 particles. The manganese-dependent increase in the rate of protein folding concurred with a specific increase in the amount of symmetric GroEL14(GroES7)2 particles detected in a chaperonin solution. Thus, Mn is a cofactor that can markedly increase the efficiency of the chaperonin reaction in vitro. Mn ions can serve as an important tool for analyzing the molecular mechanism and the structure of chaperonins.
منابع مشابه
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